Re: [RESEND RFC PATCH V3] sched: Improve scalability of select_idle_sibling using SMT balance

From: Peter Zijlstra
Date: Fri Feb 02 2018 - 15:04:39 EST


On Fri, Feb 02, 2018 at 01:34:58PM -0500, Steven Sistare wrote:
> Actually, I take back my take back. I suspect the primary benefit
> of random selection is that it breaks up resonance states where
> CPUs that are busy tend to stay busy, and CPUs that are idle tend
> to stay idle, which is reinforced by starting the search at target =
> last cpu ran.

Which, according to there here patches:

https://lkml.kernel.org/r/20180130104555.4125-1-mgorman@xxxxxxxxxxxxxxxxxxx

is a good thing, because of power management.